A film deposition apparatus (e.g., a chemical vapor deposition apparatus, a physical vapor deposition apparatus, or the like) and a plasma etching apparatus are used in the process of manufacturing a semiconductor device such as an IC (integrated circuit) and an LSI (large scale integration). These apparatuses have a stage for holding a wafer (e.g., a silicon wafer) in place with high accuracy in a vacuum processing chamber. An example of such a stage is a wafer holding apparatus that clamps a wafer with an electrostatic chuck.
A certain type of wafer holding apparatus utilizes a tray that is placed between an electrostatic chuck and a clamp object. The tray of this wafer holding apparatus has an electrode inside the tray or on the back face of the tray, so that the tray is securely held on the electrostatic chuck by a clamping force between the electrostatic chuck and the electrode of the tray (Patent Document 1, for example).
The arrangement of the electrode in the wafer holding apparatus noted above does not provide a sufficient clamping force to hold the tray on the electrostatic chuck as well as to clamp an object on the tray.
It may be desirable to provide a tray for an electrostatic chuck that is placed between an electrostatic chuck and a clamp object to provide a sufficient clamping force to clamp the object.